1. Field of Invention
This invention relates generally to the electrical stimulation devices for effecting faradic, electromagnetic or other forms of electrical stimulation, and more particularly, to a multi-functional system for this purpose capable of selectively yielding electrical stimulation signals for a broad spectrum of different biological and bio-medical applications as well as for other applications, such as electrophoresis.
2. Status of Prior Art
Electrical stimulation (ES) is widely used in biological and bio-medical research as well as in diagnostics and in clinical treatment. In faradic stimulation an intermittent or a continuous direct or alternating current or voltage is produced, whereas in electromagnetic stimulation, a current passing through a coil produces an electromagnetic field whose pattern depends on the wave form of the current.
Electrical stimulation is employed to effect nerve regeneration, in neuromuscular research, in medical diagnosis and treatment, and in pulsed voltage electrophoresis. Such stimulation is also used in bone healing and in wound healing, as well as in pain relief by means of transcutaneous electrical nerve stimulation (TENS). The use of ES to effect nerve regeneration is disclosed in the Zanakis et al. patent 4,774,967 as well as in the Borgens patent 4,919,140.
Researchers in the biological and medical sciences, physiotherapists, and clinicians who make use of ES require electrical stimulators of a type suitable for the activities in which they are engaged. Thus neurological investigators who seek to non-invasively stimulate deep nerves make use of commercially available magnetic stimulators which produce a high-intensity magnetic field pulse for this purpose.
Also commercially available are constant current stimulators for direct cortical stimulation as well as electrical stimulators for nerve and muscle stimulation procedures which generate single or double pulses, or trains of such pulses. And commercially available are wave generators capable of selectively generating sine and square wave pulses suitable for other types of electrical stimulation.
But what is not available to researchers and others who make use of electrical stimulation is a multi-functional system capable of yielding an electrical stimulation signal that is appropriate for whatever biological or biomedical application is the concern of the user of the system.
Let us assume, by way of example, that a researcher is engaged in a neurological research program in the course of which it becomes necessary to conduct tests on the effects of many different types of electrical stimuli on a certain set of nerves. The researcher would then have to assemble from different commercial sources the several electrical stimulators of different types called for by this program. This burdensome requirement adds substantially to the cost of conducting this research and to its space demands.
While the invention will be described herein as a system for producing electrical stimulating signals, the signals produced thereby can also be used for electroporation, electrophoresis (preferably pulsed voltage electrophoresis) and iontophoresis as well as for electrochemical applications as in the treatment of cancer in which a current is passed through the tissue being treated. The signals can also be used for transdermal drug delivery.
In view of the foregoing, the main object of this invention is to provide a multi-functional electrical stimulation (ES) system adapted to yield output signals for effecting faradic, electromagnetic or other forms of electrical stimulation for a broad spectrum of different biological and biomedical applications.
A significant advantage of a system in accordance with the invention is that it affords its user, whether a researcher, a diagnostician or a clinician, with whatever electrical stimulation signal is dictated by the specific type of electrical stimulation that is required. Thus if in conducting tests, a researcher needs to subject certain nerves to many different forms of electrical stimulation, the self-sufficient system, by itself and without accessories, is capable of supplying whatever electrical stimulation signals are appropriate.
Also an object of this invention is to provide a multi-functional system of the above type that includes a measuring stage that measures and displays the electrical stimulation signal operating on the substance being treated and also indicates and displays signals issuing from sensors which sense conditions prevailing in the substance, such as pH and O2, whereby the user of the system is able to observe and monitor the effects of the electrical stimulation signal he has selected.
Another object of this invention is to provide a highly-compact system of the above type which can be manufactured at relatively low cost.
Briefly stated, these objects are attained by a multi-functional electrical stimulation (ES) system adapted to yield output signals for effecting faradic, electromagnetic or other forms of electrical stimulation for a broad spectrum of different biological and bio-medical applications. The system includes an ES signal stage having a selector coupled to a plurality of different signal generators, each producing a signal having a distinct shape such as a sine, a square or sawtooth wave, or a simple or complex pulse, the parameters of which are adjustable in regard to amplitude, duration, repetition rate and other variables.
The signal from the selected generator in the ES stage is fed to at least one output stage where it is processed to produce a high or low voltage or current output of a desired polarity whereby the output stage is capable of yielding an electrical stimulation signal appropriate for its intended application. Also included in the system is a measuring stage which measures and displays the electrical stimulation signal operating on the substance being treated as well as the outputs of various sensors which sense conditions prevailing in this substance whereby the user of the system can manually adjust it or have it automatically adjusted by feedback to provide an electrical stimulation signal of whatever type he wishes and the user can then observe the effect of this signal on a substance being treated.
In another embodiment of the system, the signals from the ES signal stage are put on a bus from which they can be accessed by the output stages.
The electrical stimulation signal yielded by the system can be used for applications other than those involving electrical stimulation, such as for electrophoresis and electroporation. Or the signals from the system can be used in applications requiring mechanical or acoustic waves by applying the signal to an appropriate transducer.